Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis function is associated with major depressive disorder in adults. It is associated as well, with reactivity to stress, anxiety, and inhibited behavior in infants and children. Some young children with behavior problems (oppositional, antisocial, aggressive) also experience less obvious symptoms of depression and anxiety that may alter developmental pathways to later adjustment and disorder. The purpose of this research is to examine whether first grade children at risk for disruptive behavior disorders show different emotional and behavior problem profiles if they also show hyperactivity of HPA axis function (elevated ACTH and cortisol). Six year old children, varying in risk for chronic externalizing problems, received a physical exam. Their mothers provided a pediatric history (perinatal, developmental, and general medical). Plasma ACTH and plasma and salivary cortisol levels were assessed. Salivary cortisol was also collected early AM and prior to the physical exam. Correlations between plasma and salivary cortisol measured concurrently were moderate to substantial. ACTH and cortisol levels were examined in relation to concurrent and subsequent (3 years later) psychiatric and psychological symptoms/problems. Assessment of problems was based on multiple informants' completion of standardized, normed instruments. Elevated ACTH levels were found in children at increased risk for disruptive behavior disorders, for boys only. The most consistent index of HPA axis function for prediction of concurrent and later symptoms was elevated early morning cortisol. Internalizing and attentional problems were better predicted than externalizing, antisocial behaviors. Patterns of association did not differ markedly for boys and girls. However, there is some suggestion that HPA activity is a relatively better predictor of anxiety in girls and attentional problems in boys.